Starch conversion process



, Patented Sept. 9, 1952 UNITED STAT S PA STARCH CONVERSION PROCESS William B. Newkirk, La Grange, and John E.

Dlouhy, "Forest Park, 111., assignorsto Corn ProductsRefining Company, New York, N. Y., ,a corporation ofNew Jersey No Drawing.

--This invention relates to starch to produce dextrose containing products. More particularly it relates to the acid hydrolysis of starch to form starch hydrolysates which are free from fat and starch or starch-like products. The invention is particularly applicable to the preparation. of starch hydrolysates having low dextrose equivalent (D. E.) values, i. e. below 32. The term D. E., as used herein, refers to reducing sugar, calculated as dextrose, on dry basis. l t..\."

It has been known for a number of yearsto prepare sirups, e. g. corn sirups, from starches. These sirups are usually prepared by hydrolyzing starch with acid or enzyme to the desireddextrose equivalent value, neutralizing thehydrolyz-, ing acid or inactivating the enzyme, decolorizing with carbon and evaporating to the desired density. ,Sirups having various D. E. values have been prepared, i. e. ranging from 23 to 65. Recently, such sirups prepared from corn (maize) starch have been subjected to a drying treatment, e. g. spray drying, to form corn sirup solids.

For some application of corn sirup solids, it is desirable that such solids have a low D. E. value. This is particularly true where sweetness is not the main requirement and where high molecular Weight bodies such as dextrins are required. However, such low D. E. products, i. e. having a D. E. value below about 32 usually always contain some unconverted starch or starch-like bodies which react positively to the usual methods of testing for the presence of starch- The presence of starch or starch-like bodies is objectionable in certain applications of starch hydrolysates. For example, these bodies have a tendency to cloud the sirup made therefrom. Low D. E. products, particularly when prepared from corn starch, also contain fat which is not removed bythe usual refining methods. The presence of fat is objectionable because it develops oif odors and flavors in the product.

An object of the present invention is to produce a starch hydrolysate which may have a low D. E. value and yet be free of starch and starchlike bodies and also fat. A further object is the preparation of a sirup from starch which sirup;

the hydrolysis of has the aforesaid properties. Still another object is the preparation of a corn sirup solids product having such properties. A further objectis the provision of methods whereby the aforementioned products may be prepared. Further objects will appear more fully hereinafter;

We havenow found that we ,canlproduce a starch hydrolysate having a low, D. E. value {and Application November 15, 1949, Serial No. 127,522

8 claims. "(01. 127 4o) which is free of starch or liquor before or after neutralization to a temperature within the range of about F. to about F. and maintaining the temperature of the tuber starch there maybe added to the hydroly sate before or after the neutralization and cooling l but priorto the holding steps certain adjuncts.

The invention also contemplates the application of, the cooling and holding treatment as afore mentioned to acid starch hydrolysate liquor which i has been prepared by hydrolysis involving a long. holding time in the converter, e. g. up to 2hours or more, as well as to acid starch hydrolysate liquor prepared in conventional manner wherein the time for the conversion than 45 minutes, 15 to30 minutes being the aver-' age time. A continuous converter of the type to a long holding time for the conversion. The purpose of the cooling and holding steps is to allow any starch or starch-like bodies to react; with the fats present in the hydrolysate to form an insoluble starch-fat complex, which can then be removed as by filtration. The term fat starch complex includes starch-like bodies which form complexes with fatty materials. In usual commercial practice in preparing sirups, the hydrolysate is filtered immediately after neutraliza However, it

tion to remove the fatty material.

has been found that in hydrolysates having low D. E. values, the fatty material is not as easily starches are used as starting materials, addi tional amounts thereof may be added to the hydrolysate or the fatty material may be addedin the form of an adjunct.

In carrying out the present invention, a starch slurry, e. g. corn starch havingadensity of (18 to starch-like bodies, and

also fat, and which is readily adapted toconcentration to a sirup or dried to a solid product in amorphous form. In general, our invention embraces cooling the acid starch hydrolysate is generally not more which will be described hereinafter lends itself present in suificient quan' tity, as is likely to be the case when root or tuber D. E. level .is-attained. The pH of. such hydro-- lysate is tlien adjusted. tolabout .5.0:or below with. 1

sodium carbonate or other suitable alkaline material. The hydrolysate is then cooled to a tem-;. perature within the range of about 60 F. to about 140 F. and such temperature is maintained fora period of at least one hour orzsui'fieiently. long-,tog permit the formation of thefat.starchcomplem- As an optional step, a small'famountf'of'ran ad l" Acid starchhydrolysate liquors having D. E. valjunct, e. g. a soap such as sodium stearate, may

be added before or after the pH adjustment, v if the amount of fat present in tlie'liydr'oly'sate:

then treatedin the customary. manner. with." decolorizing "and refining carbon and concentrated to-thedesired density 1.01 dried,.;aszby: spray. dry-.

ing

Incarrying; out the. processzof the present; in:- vention,; using corn starch .or. sorghum grainstarch, ,itha's been found that ordinarily-there" is sufficient fatty material presenti'in'the. hydro'--- lysate toreactwithall of. the unconverted-starch oig starch-liket bodies.- However; if.- suchis not theqcase, additional, fatty, materialobtainedrfrom starchhydrolysatesmay be added. 01" the fatty.

material-may be addedin thexform of arfatty" convertedstarch or starch-like bodies.

the invention is generally applicable to acid "starch -hydrolysate liquors having D. E. values go anywhere below 32, it isznot practical to apply Thereafter, the hydrolysate is"sub- 5 two hours, is preferred. A holding period of more than;two hours isnot detrimental but 'does not inereaseithe; formation ofv .the.ffat-starch complex.

q The fat-starch complex may be removed by any suitable method such as by filtering or centrifuging-r The.= principlesof: the present invention are applicablezto acidstarch hydrolysate liquors haviiigziDli.Eavaluesr'ranging from about 10 to 32.

uesabove 32.do.not.- ordinarily contain any un- While it: to liquors-.having D. values below about. 10.

The.continuoussconverter generally consists 10ft.

anientry; chamberwhere acidified starch: suspen;

converter is equipped with suitable valves and level:..controlsr to cmaintain a. ,continuousa fiow throughthe; system at. the desired flow rate;

. Thefollowing examples which 3 are. intendedas i Una-soap, Among. t adjun t Whichmay- 5%;.informativeandi typical only. andnot in: alimite beused for purposes of the present invention are soluble: soaps such asuhouseholdsoaps; sodium.

stearate; palmitic acid, stearic acidyoleic -acid,

acid and solublesoaps derived from .such acids.

and mixtures; of. such soaps and acids.

The. amount. of. the adjunct added may vary:

according to the amount of. fatty material pres entiinthe.hydrolysate.. Anexcess of'theiadjunct *tre'ated witlrcarb'on to decolorize andfinally Such/spray dried material gave a positive reaction when tested by itherA; 0. A. C1 method of testing-forthe presence of-starcli-but':

isniot detrimental as far asthe formation-.of'ithe. complex isconcerned but is not necessary to :its.

formation, the theoretical amount a being suifie cient. Amounts in excess of about 1.75 percent,

uct! Ifan'adjunctis'to be added to the-hydrolysate for purposes ofthe present invention,

itiisipreferaible to add it to the hydrolysate beforeIneutralization, although this is not essen tiall Starch -hydrolysates whichv arev to be. used inth'e' production of. sirups are ordinarilynew trjalizedto' a pH of about 5. At this pH the fatty.

and colloidal materials present. in the :hydroly.

sate coagulatemore readily, and,.hence, are more easily "re-moved. by filtration. Further, it. is

known that sirups having a .pH above about. 5 or: 5 5I5fhave a tendency. to darkenv in color. Therefore,.if the adjunct added-has aneffect. 011131181 pI-Lvalue, itis preferable .to addittothe-liy-r;

drolysatebefore.neutralizationto a pI-Iof about 5; However,,the. holding step may be effectedat: a;- pI-Ilbetween about.2.0 and,about.9-.0. Y

I'heltemperature of the hydrolysate duringthe: holding period should be within, the .range'aof about Fgtoabout .140? E: .The." preferred temperature'iseabout.100 i;

ing sensezwill. further: illustrate. the invention:

Efcdmplel."

A corn starch: slurry having-1a; density of 18 Ed... 40 was =converted in. a. continuous converter with 0.016 N sulfuricacid to a' D. E; value'of about lfi.

The hydrolysate: was then treated i with bentoniteto remove fatty and colloidal .materials', then filtered, the filtrate neutralized to; a pI-I of "14.8,

spray dried.

contained substantiallymo fat. 4

A- sample of such spray: dried: material: was" dis solved in: water to=form a :solution. havinga density of 15.0 B. at 60 To thesolution Was'.- added 35:ml. of 0.1. N sodium: stearatelper. liter: of.

solution to assure thepresence of: suiiicient; fatty .materialfor formation of the starchfatcomplex'.

The'pI-I; of. the'iresulting solutionv was then: adi- I justed to 3.5;. The: temperature of 1 such solution.

wasadjusted to F.1andsuch temperaturezwas: maintained for aperiod of two hours, thereafter- 50 the solutioniwasfiltered. Itwas foundEsuch:solus.-.

tion illOW contained-J substantially: no starcli or: starch-like bodies when tested:.by theistandard..

iodine method. for: the presence-10f starch;

Example. '11.

dr'ochloriczacid ascatalyst, the mixture was con- 7 vertedzint anautoclave with" a steam. pressurebf- 1 11p;szitforsaperiod' of. onehour. The hydrolysat'e whichrhad a D. E.v value ofi 15.1 was neutralized- 2 with sodium hydroxide ma pH 'of 4.5andsepaeratedsintotwo parts. Part' A was filtered and :mtredtladlitvithi carbon: immediately whereas Earth- The. 1 continuous.

B was cooled to 100 F. and maintained at this temperature for two hours after which it was filtered and treated with carbon. Finished samples of liquors A and B were then tested qualitatively by the starch iodine test for the presence of starch. The amount of material which precipitated as a complex with iodine was also measured to determine how much starch was present. The results are summarized in the table which follows Example III.

Example 11 I An acidified starch slurry identical to that used in Example II was prepared and converted at 1'7 p. s. i. steam pressure for 20 minutes. The hydrolysate had a D. E. value of 13.8 and was treated as in Example II. The results are shown in the table.

The above results show that the B liquors of Examples II and III processed by the method of this invention, unlike the A liquors which were processed by the conventional methods, showed negative qualitative results for starch by the standard iodine test and also contained no or barely detectable amounts of material which precipitated as a complex with iodine.

The B" liquors after the cooling and holding treatment were also substantially free of fat.

1. In the process of preparing sirups from acid starch hydrolysate liquors having a D. E. value within the range of about to about 32 by hydrolyzin starch with acid to a predetermined D. E. value followed by neutralization of the acid in the liquor to a pH of about 5 and refining and evaporating the liquor, the improvement which comprises adding to the liquor prior to neutralization a sufiicient amount of material from the group consisting of fatty acids derived from the hydrolysis of corn starch; fatty acids derived from the hydrolysis of sorghum grain starch; household soaps; sodium stearate; pahnitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, lignoceric acid, myristic acid, lauric acid, capric acid; soluble soaps derived from such acids, and mixtures of any of such soaps and acids, to react with the starch and/0r starch-like bodies present to form a complex with the starch, cooling the liquor to a temperature within the range of about 60 F. to about 140 F. and maintaining the temperature of the cooled liquor within such range for at least one hour, and thereafter removing the fat-starch complex from the liquor.

2. The process of preparing a sirup which may be dried to solid amorphous form which comprises converting starch with acid to produce a starch hydrolysate liquor with a D. E. value of about 10 to about 32, adding to the liquor an adjunct from the group consisting of fatty acids, derived from the hydrolysis of corn starch; fatty acids derived from the hydrolysis of sorghum grain starch; household soaps; sodium stearate; palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, lignoceric acid, myristic acid, lauric acid, capric acid, soaps derived from such acids, and mixtures of any of such soaps and acids, to react with the starch and/or starch-like bodies present, cooling the liquor to about 60 F. to about 140 F., adjusting the pH to about 2 to 9, maintaining the temperature of the liquor within the range of 60 F. to 140 F. for at least one hour to allow the formation of fat-starch complex, removing the fat-starch complex, and thereafter decolorizing and concentrating the liquor.

3. The process of preparing a sirup which may be dried to solid amorphous form which comprises converting starch with acid to produce a starch hydrolysate liquor with a D. E. value of about 10 to about 32, adding to the liquor fatty acids derived from the hydrolysis of starch with acid, to react with the starch and/or starch-like bodies present, cooling the liquor to about 60 F. to about 140 F., adjusting the pH to about 2 to 9, maintaining the temperature of the liquor within the range of 60 F. to 140 F. for at least one hour to 7 allow the formation of fat-starch complex, re-

moving the fat-starch complex, and thereafter decolorizing and concentrating the liquor.

4. The process accordin to claim 3 wherein the added material is sodium stearate.

5. The process according to claim 3 wherein the added material is the fatty material obtained by the hydrolysis of corn starch.

6. The process according to claim 1 wherein the added material is household soaps.

7. The process according to claim 1 wherein the added material is the fatty material obtained by the hydrolysis of corn starch.

8. The process according to claim 3 wherein the added material is the fatty material obtained by the hydrolysis of sorghum grain starch.

WILLIAM B. NEWKIRK. JOHN E. DLOUI-IY.

REFERENCES CITED The following references are of record in the,

Name Date Fell Jan. 2, 1883 Number 

1. IN THE PROCESS OF PREPARING SIRUPS FROM ACID STARCH HYDROLYSATE LIQUORS HAVING A D. E. VALUE WITHIN THE RANGE OF ABOUT 10 TO ABOUT 32 BY HYDROLYZING STARCH WITH ACID TO A PREDETERMINED D. E. VALUE FOLLOWED BY NEUTRALIZATION OF THE ACID IN THE LIQUOR TO A PH OF ABOUT 5 AND REFINING AND EVAPORATING THE LIQUOR, THE IMPROVEMENT WHICH COMPRISES ADDING TO THE LIQUOR PRIOR TO NEUTRALIZATION A SUFFICIENT AMOUNT OF MATERIAL FROM THE GROUP CONSISTING OF FATTY ACIDS DERIVED FROM THE HYDROLYSIS OF CORN STARCH; FATTY ACIDS DERIVED FROM THE HYDROLYSIS OF SORGHUM GRAIN STARCH; HOUSEHOLD SOAPS; SODIUM STEARATE PALMITIC ACID, STEARIC ACID, OLEIC ACID, LINOLEIC ACID, LINOLENIC ACID, ARACHIDIC ACID, LIGNOCERIC ACID, MYRISTIC ACID, LAURIC ACID, CAPRIC ACID; SOLUBLE SOAPS DERIVED FROM SUCH ACIDS, AND MIXTURES OF ANY OF SUCH SOAPS AND ACIDS, TO REACT WITH THE STARCH AND/OR STARCH-LIKE BODIES PRESENT TO FORM A COMPLEX WITH THE STARCH, COOLING THE LIQUOR TO A TEMPERATURE WITHIN THE RANGE OF ABOUT 60* F. TO ABOUT 140* F. AND MAINTAINING THE TEMPERATURE OF THE COOLED LIQUOR WITHIN SUCH RANGE FOR AT LEAST ONE HOUR, AND THEREAFTER REMOVING THE FAT-STARCH COMPLEX FROM THE LIQUOR. 